On Friday, October 26th, the U.S. Court of Appeals for the Federal Circuit issued a nonprecedential decision in BASF Corporation v. Enthone, Inc. which vacated an earlier decision stemming from an inter partes review (IPR) proceeding at the Patent Trial and Appeal Board (PTAB) which had upheld a patent owned by Enthone as valid over an obviousness challenge asserted by BASF. The Federal Circuit panel of Circuit Judges Timothy Dyk, Evan Wallach and Richard Taranto remanded the case to the PTAB after holding that certain findings made by the PTAB were inadequately supported or explained.
The patent-at-issue in this appeal is U.S. Patent No. 7303992, titled Copper Electrodeposition in Microelectronics. Issued to Enthone in December 2007, it covers a method for electroplating a copper deposit onto a semiconductor integrated circuit device substrate with electrical interconnect features including submicron-sized features having bottoms, sidewalls and top openings in such a way where the copper deposition in a vertical disposition from the bottoms to the top openings of the features is greater than the copper deposition on the sidewalls. The resulting invention enables the use of copper to substitute aluminum in semiconductor substrates while eliminating defects that can form during copper deposition.
BASF petitioned the PTAB to challenge the validity of the ‘992 on 35 U.S.C. § 103 grounds as obvious and the PTAB instituted the IPR on 24 challenged claims of the ‘992 patent. BASF argued that challenged claims were invalid as obvious based on two collections of asserted prior art. The first was U.S. Patent No. 6444110, Electrolytic Copper Plating Method (“Barstad”) in view of U.S. Patent Application No. 20020127847, Electrochemical Co-Deposition of Metals for Electronic Device Manufacture (“Alling”) and a 1989 BASF catalog for Pluronic and Tetronic block copolymer surfactants. The second was U.S. Patent Application No. 20020043467, Electrolyte (“Morrissey”) in view of Alling and the 1989 BASF catalog. The PTAB terminated the IPR finding that BASF did not prove the invalidity of the challenged claims by a preponderance of the evidence.
On appeal, BASF argued that the PTAB applied an overly stringent version of the motivation to combine test leading to the Board’s decision to uphold the ‘992 patent’s validity. The PTAB found that Alling didn’t provide the requisite motivation to combine the Tetronic copolymer in the BASF catalog with the superfilling method found in either Barstad or Morrissey. However, the Federal Circuit found that the PTAB adhered to the appellate court’s precedent in considering whether the level of unpredictability in the art demanded that BASF demonstrate a more definite motivation to combine the prior art in the manner alleged within BASF’s petition. Thus, the CAFC concluded that the PTAB didn’t apply an incorrect legal standard in its motivation to combine analysis.
BASF also argued that the PTAB’s nonobviousness findings either lacked support in the cited evidence or were inadequately explained, an argument with which the Federal Circuit agreed. The appellate court found that the PTAB failed to support its finding that a person having ordinary skill in the art wouldn’t have found Alling applicable to superfilling. The PTAB’s only support for this finding was a single passage cited from Enthone’s expert declaration and Enthone admitted in oral argument that the PTAB failed to support its finding.
The Federal Circuit also found that the PTAB acted arbitrarily and capriciously for reaching a conclusion regarding Barstad which was inconsistent with its findings in an IPR proceeding between the same parties on a different patent where BASF asserted the same combination of prior art. In the IPR on the ‘992 patent, the PTAB found that Barstad disclosed Tetronic copolymers as surfactants and thus they couldn’t be suppressors. In the other IPR, the PTAB found that Barstad disclosed the Tetronic copolymers as surfactant-type suppressor agents. The Federal Circuit panel found that these separate findings were plainly inconsistent. On remand, the Federal Circuit directed the PTAB to reconsider whether either the asserted combinations of prior art provide the requisite motivation to combine Alling with the other art, and to reevaluate whether Barstad discloses Tetronic copolymers as suppressors for use in superfilling.